1. Field of the Invention
The present invention relates generally to safety buckles used with a strap, and relates more particularly to child resistant safety buckles for securing a child in a seat.
2. Description of the Related Art
Child resistant safety buckles are used in a number of applications including securing children in car seats, high chairs and shopping carts. A particular type of safety buckle is child resistant, to prevent children under a given age from releasing the buckle and freeing themselves, leading to a potentially dangerous or injurious situation. Although children under a certain age are prevented from unclasping the buckle, adults typically have no difficulty in disengaging the buckle to free the child. One type of buckle that is child resistant but can be opened by an adult has a double action feature to permit the buckle to be opened. That is, the buckle is opened by operating several disengaging elements to unlatch the buckle and disengage the buckle portions. By providing two actions to allow the buckle to be opened, the buckle is made child resistant, because a typical child under a certain age is unable to properly operate the two features, either sequentially or at the same time, for example, to unlatch and open the buckle. At the same time, an adult can easily and intuitively disengage the buckle by operating the two features as required.
A number of buckles are available that, while not designed to be child resistant, are provided to withstand heavy loading, so that the buckles will not disengage unexpectedly. These types of buckles also have a multi-open feature, in that a number of operations must be conducted on the buckle to permit the buckle to be unlatched and opened. Typical applications for these type of buckles involve heavy duty or industrial uses, such as clasps for utility belts, sportswear or other applications, where the buckle is subjected to high loading or must be well secured.
One such high security buckle is shown in U.S. Pat. No. 5,774,956 to French et al., which discloses a buckle with flexible side release latches and a third latch accessible on the front of the buckle. The male portion of the buckle includes a central latch arm that engages the female portion of the buckle in a central portion, and is released by pressing on a central button on one side of the female buckle portion. The buckle unlatches when both side latch arms are moved inwardly, and the central arm is moved away from the catch on the female portion. The buckle unlatches when all three arms are moved to unlatched positions simultaneously. Changing the orientation of the male portion when inserted into the female portion results in the central arm catch being defeated, because there is no corresponding catch cooperation on the back side of the female.
U.S. Pat. No. 5,991,985 to Galbreath discloses a safety buckle with side catch arms and a central catch that engages with a depressible button catch on the female portion of the buckle. To disengage the buckle, the central button on the female portion of the buckle is depressed to either disengage from the central arm or displace the central arm to disengage from a catch. If the male portion of buckle is inserted into the female portion of the buckle in an opposite orientation so that the central arm does not engage the depressible button catch, the buckle either does not clasp or the central arm does not latch.
U.S. Pat. No. 6,311,374 to Anscher shows a two-operation buckle with a center arm that includes a push button near the base of the male member with a catch near the push button to engage an opening catch in the female member when the buckle portions are engaged. In this configuration, it is somewhat difficult to depress the push button on the center arm of the male member to disengage the latch button from the opening in the female member. That is, the push button on the center arm near the base of the male member requires more leverage to displace the center arm to free the center latch from the opening in the female member. The additional leverage required, coupled with the need to depress the side arms together to unlatch the buckle, makes the configuration difficult for adults and children alike to disengage the buckle. In addition, the buckle is non-reversible, i.e., if the male member is inserted in an opposite orientation, so that the push button faces the back of the buckle assembly, the male and female members do not engage with each other.
U.S. Pat. No. 6,684,466 to Nishida et al. teaches a two-operation safety buckle in which the male member has a center arm with a catch recess that engages a catch on the female member. The center arm of the male member is displaced downwardly during insertion to permit the latch member to protrude into the latch recess when the male member is fully inserted and the center arm returns to its undisplaced position. The center arm is disengaged from the catch with a button on the female member that is pressed to displace the center arm away from the catch of the female member, so that the male member can be withdrawn from the female member, with the sidearms being depressed together. This buckle configuration is not reversible, in that if the male is inserted in an opposite orientation, the center arm does not latch with the female latch member. For example, if the buckle deforms, a situation where the buckle is able to be clasped but not unclasped may occur.
U.S. Pat. No. 6,138,330 to Galbreath discloses a two-operation safety buckle in which the sidearms of the male member are prevented from being depressed together to unlatch the buckle, when the male and female members are engaged together. A blocking device in the female member engages with the latching arms of the male member to prevent their displacement and thus prevent them from being unlatched until the blocking member is displaced away from the latching arms to permit their relative movement. Accordingly, the blocking member is first displaced, and then the arm latches are displaced towards each other until they are free of their respective latches in the female member, at which point the male member can be withdrawn from the female member. The configuration of this buckle permits the male member to be inserted in an opposite orientation, however the buckle is difficult to manufacture due to practical tolerance limitations in the materials. In addition, the buckle configuration is not designed to withstand high impact or compressive forces that are typically encountered in safety buckle applications.
In each of the above two-operation safety buckles, a change in the orientation of the male member when being inserted into the female member causes the buckle either not to clasp, or defeats the operation of the second operation needed to unclasp the buckle. In a case of the '330 patent to Galbreath, reversing the orientation of the male member does not defeat the two-operation feature of the buckle, however, the buckle operates by preventing the latching arms of the male member from being displaced to be unlatched, which impairs the manufacturability of the buckle and creates difficulties for the user in unlatching the buckle. In addition, there are challenges to making the buckle of the '330 patent to Galbreath impact resistant or durable in stressful environments. For example, if the buckle becomes deformed due to impact or compression, it is extremely difficult to unlatch the buckle.
Accordingly, it would be desirable to obtain a two-operation safety buckle that is independent of the orientation of the male member in the female member that provides robust operation in practice with ease of manufacturability.